KI front panel "VOLTAGE" adjust?

I know on the SDS Sigma, margins were adjustable in a step up or down from normal via a 3 position switch on the control panel/ This signal was chained thru all the core memory power supplies. circa 1969 and before. On Tue, Aug 13, 2013 at 11:06 AM, John Wilson <wilson at dbit.com> wrote: > On Tue, Aug 13, 2013 at 06:15:41AM -0500, Chris Elmquist wrote: >> Interesting pictures. I am curious why machines of this era often have >> a "VOLTAGE" adjustment on the front panel? Was it really neccessary >> for an operator to adjust some voltage setting as the machine ran thus >> requiring that adjustment to be easily accessible on the front panel? > I dimly remember (probably from the Gordon Bell book?) that KO+crowd > were weirdly obsessed (or maybe normally obsessed given the known failure > modes of the time) with marginal testing. So they liked to crank things > up to the high and low limits every so often to find parts that were about > to stop working at the nominal voltages. So I think that's what that is... > > John Wilso > D Bit >